1. Field of the Invention
The present invention is related to an LED bulb, and more particularly to a bending LED bulb that can provide uniform luminance and dissipate out heat generated by LEDs.
2. Description of the Related Art
Ball-type bulbs and incandescent tubes for lighting purpose in early stage are all quite common.
In view of the awakening energy-saving consciousness, energy-saving bulbs, such as U-shaped bulb, 2C type bulb and helical bulb, have started their entry in the light market. In spite of being more energy-saving, LED bulbs with more energy-saving capability overwhelm the glamour of the earlier energy-saving bulbs to become the new favorite in the market after high power white light LED technique become mature.
With reference to FIGS. 13 and 14, a conventional LED ball-type bulb 30 has a base 31, an LED substrate 32 and a glass cover 33.
The base 31 has a free end, a base electrode 311 and a bottom electrode 312. The base electrode 311 takes a form of threads formed around the base 31 for screwing into a screw lamp socket. The bottom electrode 312 is formed on a bottom of the base 31.
The LED substrate 32 is securely mounted on an end of the base 31 opposite to the free end, and has a rigid circuit board 321, a plurality of light-emitting diodes (LED) 322 and a heat sink 323. The rigid circuit board 321 is electrically connected to the base electrode 311 and the bottom electrode 312. The LEDs 322 are mounted on a top of the rigid circuit board 321 in a form of a matrix pattern. The heat sink is mounted on a bottom of the rigid circuit board 321. The glass cover 33 is securely mounted on the base 31 to cover the LED substrate 32 therein.
As the candle (cd) of a bulb for lighting must reach a standard value, the LED bulb 30 needs to employ a plurality of LEDs, for example, as shown in FIG. 14, to meet that end. LED is well-known in consuming less power, yet a layout of the LEDs 322 ends up with a shorter life duration of the LED bulb 30 because of heat generated from the LEDs 322. After a long term of operation, the accumulated heat escalate the temperature of the overall LED bulb 30. In particular, the LEDs 322 that centrally located have a higher temperature than that of other LEDs 322 and are prone to damage. Hence, LED bulbs or tubes with similar LED layout have to be arranged with additional heat dissipation structure and this increases the cost for manufacturing the LED bulb 30.
Furthermore, there are plenty of ball-type LED bulbs and LEDs tubes currently available in the marketplace, while energy-saving bending LED tubes haven't been absent in the market so far. If the heat dissipation issue of the LEDs can be solved, LED bulbs can be further promoted as the new-generation energy-saving lighting source.